钙对高温胁迫下烟草幼苗抗氧化代谢的影响

Effect of Calcium on the Heat Tolerance and Antioxidant Metabolism of Tobacco Seedlings

用10mmol LCaCl2溶液处理烟草幼苗,能减缓高温胁迫所引发的一些胁变反应,如叶绿素破坏、积累膜脂过氧化产物MDA,增加细胞膜相对透性,降低内源抗氧化剂(AsA,GSH)和脯氨酸含量.在高温胁迫下,SOD和CAT等抗氧化酶活性呈现先升后降的变化趋势.恢复生长以后,钙处理和未处理的烟草幼苗其内源抗氧化剂含量和抗氧化酶活性均有不同程度的回升.由此认为,高温胁迫后烟草幼苗体内抗氧化酶活性受抑,活性氧积累以及由此引发的膜脂过氧化作用是烟草幼苗高温伤害的原因之一.

After treatment the tobacco seedlings with 10?mmol/L CaCl2 solution,the effect of calcium on antioxidant metabolism under high temperature stress in tobacco seedling leaves was studied.The results showed that calcium could extenuate the change of stress under heat stress by 40?℃ temperature,such as the destruction of the chlorophyll,the accumulation of MDA and increase relative plasmalemma permeability in tobacco leaves.It indicated that calcium also increased the content of endogenous antioxidant (AsA,GSH )and enhanced the accumulation of proline in leaves at 40?℃.The activities of superoxide(SOD) and catalase (CAT) in the tobacco seedlings went up at beginning and then lowered during 40?℃ temperature stress.These results suggest that Ca2+ treatment increased activities of antioxidant systems under high temperature stress.After recovery growth,the endogenous antioxidant and antioxidant enzyme in Ca2+ treatment and control seedlings were rose in different degrees.According to these results,it is thought that the inhibited activities of antioxidant systems and the accumulation of active oxygen species by initiation of membrane lipid peroxidation may be a cause to the injury of high temperature stress to tobacco seedlings.